Linux Kernel Debugfs dentry Leak and Error Handling Issue

CVE-2026-64147

What is CVE-2026-64147?

A vulnerability in the Linux kernel's debugfs mechanism allows for a dentry leak due to improper handling of reference counts. The function debugfs_lookup() returns a dentry with an elevated reference count that must be released properly using dput(). The existing implementation fails to release the dentry during firmware reset recovery, leading to a persistent reference leak. Additionally, when CONFIG_DEBUG_FS is not enabled, the function correctly returns an error pointer (ERR_PTR(-ENODEV)). However, the current error handling logic can mistakenly attempt to call dput() on an invalid pointer, resulting in system crashes. This vulnerability highlights the need for improved memory management and error handling in kernel-level code.

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